Autocad - Revit - Bluebeam
These three pieces of software are essential to the design and construction of a building. I am familiar with all of them and was formerly certified in Autocad and Revit. While these are not used daily by on site management, I believe it is a useful skill because it streamlines the RFI process by helping provide clearer explanations to architects and engineers as to our exact questions. Bluebeam however is used almost daily as both a planning tool and explanation tool for helping our subcontractors get the exact information they need to do their work.